DirectX-XShm now waits for the X server to finish the previous frame
before sending another frame down its pipe, avoiding the X server
overload and resulting slowness that used to be.

diff --git a/tsx11/X11_calls b/tsx11/X11_calls
index 65c747b..b872337 100644
--- a/tsx11/X11_calls
+++ b/tsx11/X11_calls
@@ -16,6 +16,7 @@
 XChangeKeyboardControl
 XChangeProperty
 XChangeWindowAttributes
+XCheckTypedEvent
 XCheckTypedWindowEvent
 XCheckWindowEvent
 XClipBox